The present invention relates to a wrapping apparatus and more particularly to a shuttle or wrapping material carrier change system and method for a wrapping apparatus.
Certain items are packaged in roll or coil form. For example, steel and aluminum sheet are often coiled for storage, transport, and handling. Such coils can be up to five to seven feet in diameter.
In order to protect and preserve the appearance of the steel or aluminum, the coils are typically wrapped with protective material in the form of a film. Such a film can be a single wrap of, for example, a low density polyethylene stretch film. The wrap can also include a fabric or other woven or non-woven material wrapped along with the polyethylene film.
One known machine for carrying out the wrapping process uses a specifically shaped track to carry a film dispensing shuttle through the eye of the coil, while the coil is slowly rotated on its axis on a set of block rollers. The complete body of the coil is effectively sealed by a cocoon of stretch film.
Generally, the machine has a heavy-duty, generally oval shaped track that provides the guide for the film-dispensing shuttle that travels around the inside of the track. The track has a hinged end section or arm that pivots upwardly to open the track so that a lower portion of the track can be moved into the eye of the coil. The track is adjustable in the vertical plane to accommodate different coil diameters.
The track is typically movable on rails to advance into the eye of the coil. The machine can also be movable transverse to the direction of the track. Such a machine is commercially available from ITW Fleetwood-Signode of Glenview, Ill., under the name CoilMaster.
The film dispensing shuttle is designed to drive itself around the track. In a present system the shuttle includes a drive element (referred to as a tractor) and one or more film dispensing elements (each referred to as a trailer). The tractor and trailers are separate from, but operably connected to one another such that the tractor drives (pulls) the one or more trailers, and so that the tractor and trailer(s) can be separated from each other for maintenance, repair, replacement or the like.
The film is provided on the shuttle in rolls. The rolls have a finite amount of material wound thereon and as such require periodic replacement. Depending upon the size of the coil, a roll of film can last for perhaps as few as two or three coils. As such, the film rolls on the shuttle may have to be replaced fairly frequently. In known machines, the task of replacing the film and the shuttles is labor intensive and time consuming, thus quite costly.
To replace a film roll, the machine has to be shut down and the hinged track end opened. If a “tail” of the film is hanging from the coil, the tail is tucked into the wound film to prevent the tail from interfering with movement of the shuttle. The shuttle is positioned along the track at a predetermined location and the track is then withdrawn from the coil.
Following withdrawal of the track, a film roll is replaced in the shuttle. The track is then moved back into place in the eye of the coil, the hinged end is lowered and the track is closed. A leading end of the film is secured and the shuttle is restarted. Given that these machines are quite large, the entire film roll replacement procedure takes a considerable amount of time and requires a considerable amount of labor.
Accordingly, there is a need for a system and method for changing out a shuttle that precludes the need to remove the track from the eye of the coil. Desirably, such a system and method are carried out with the track in place in the coil. More desirably, such a system and method uses a ready substitute shuttle to further reduce the downtime necessary to place the machine back into service.